1. Field of the Invention
The present invention relates generally to methods for forming carbon doped silicon containing dielectric layers within microelectronic fabrications. More particularly, the present invention relates to methods for forming, with enhanced adhesive properties, carbon doped silicon containing dielectric layers within microelectronic fabrications.
2. Description of the Related Art
Microelectronic fabrications are formed from microelectronic substrates over which are formed patterned microelectronic conductor layers which are separated by microelectronic dielectric layers.
As microelectronic fabrication integration levels have increased and microelectronic device and patterned microelectronic conductor layer dimensions have decreased, it has become increasingly common in the art of microelectronic fabrication to employ interposed between the patterns of patterned microelectronic conductor layers when fabricating microelectronic fabrications microelectronic dielectric layers formed of comparatively low dielectric constant dielectric materials having dielectric constants in a range of from about 2.0 to about 4.0. For comparison purposes, microelectronic dielectric layers formed within microelectronic fabrications from conventional silicon oxide dielectric materials, silicon nitride dielectric materials and silicon oxynitride dielectric materials typically have comparatively higher dielectric constants in a range of from about 4.0 to about 8.0.
Microelectronic dielectric layers formed of comparatively low dielectric constant dielectric materials are desirable in the art of microelectronic fabrication formed interposed between the patterns of patterned microelectronic conductor layers within microelectronic fabrications insofar as such microelectronic dielectric layers formed of dielectric materials having comparatively low dielectric constants provide microelectronic fabrications which may theoretically operate at higher microelectronic fabrication speeds, with attenuated patterned microelectronic conductor layer parasitic capacitance and attenuated patterned microelectronic conductor layer cross-talk.
Of the comparatively low dielectric constant dielectric materials which may be employed for forming microelectronic dielectric layers within microelectronic fabrications, carbon doped silicon containing dielectric materials, such as carbon doped silicon oxide dielectric materials, carbon doped silicon nitride dielectric materials and carbon doped silicon oxynitride dielectric materials, are presently of interest. Carbon doped silicon containing dielectric materials, such as carbon doped silicon oxide dielectric materials, carbon doped silicon nitride dielectric materials and carbon doped silicon oxynitride dielectric materials, are presently of considerable interest insofar as carbon doped silicon containing dielectric materials may be formed employing chemical vapor deposition (CVD) methods and plasma enhanced chemical vapor deposition (PECVD) methods as are generally otherwise conventional in the art of microelectronic fabrication, but with appropriate modification of source materials and/or deposition parameters such as to provide when forming a microelectronic dielectric layer within a microelectronic fabrication a carbon doped silicon containing dielectric material rather than a conventional silicon containing dielectric material.
While carbon doped silicon containing dielectric materials, and in particular carbon doped silicon oxide dielectric materials, are thus desirable in the art of microelectronic fabrication for forming microelectronic dielectric layers within microelectronic fabrications, carbon doped silicon containing dielectric materials are in turn nonetheless also not entirely without problems in the art of microelectronic fabrication for forming microelectronic dielectric layers within microelectronic fabrication. In that regard, it has been observed in the art of microelectronic fabrication that carbon doped silicon containing dielectric materials when employed for forming microelectronic dielectric layers within microelectronic fabrication often provide inadequate adhesion with respect to additional microelectronic layers formed upon the microelectronic dielectric layers formed of the carbon doped silicon containing dielectric materials.
It is thus desirable in the art of microelectronic fabrication to provide microelectronic dielectric layers formed of carbon doped silicon containing dielectric materials, and in particular of carbon doped silicon oxide dielectric materials, having comparatively low dielectric constants, but also with enhanced adhesion with respect to additional microelectronic layers formed thereupon.
It is towards the foregoing object that the present invention is directed.
Various methods and materials have been disclosed in the art of microelectronic fabrication for forming microelectronic layers, and in particular microelectronic dielectric layers, with desirable properties in the art of microelectronic fabrication.
For example, Hochberg et al., in U.S. Pat. No. 4,992,306, disclose a low pressure chemical vapor deposition (LPCVD) method for forming, at a comparatively low deposition temperature of from about 325 to about 700 degrees centigrade, and with a comparatively high deposition rate, a silicon oxide dielectric layer, a silicon nitride dielectric layer or a silicon oxynitride dielectric layer within a microelectronic fabrication. In order to realize the foregoing result, the low pressure chemical vapor deposition (LPCVD) method employs in conjunction with an oxidant source material a silicon source material comprising a two or greater carbon atom content alkylazidosilane, arylazidosilane or alkylarylazidosilane.
In addition, Yau et al., in U.S. Pat. No. 6,054,379 and U.S. Pat. No. 6,072,227 disclose, in conjunction with a microelectronic structure resulting therefrom, a method for forming, with enhanced barrier properties and with enhanced etch stop properties, a microelectronic dielectric layer formed of a lower dielectric constant dielectric material within a microelectronic fabrication. In order to realize the foregoing result, the method employs when forming the microelectronic dielectric layer a plasma enhanced chemical vapor deposition (PECVD) method employing a silicon source material comprising an organosilane, preferably methylsilane, along with an oxidant source material, preferably nitrous oxide.
Desirable in the art of microelectronic fabrication are additional methods and materials which may be employed for forming within microelectronic fabrications microelectronic dielectric layers formed of carbon doped silicon containing dielectric materials, and in particular of carbon doped silicon oxide dielectric materials, having comparatively low dielectric constants, but also with enhanced adhesion with respect to additional microelectronic layers formed thereupon.
It is towards the foregoing object that the present invention is directed.
A first object of the present invention is to provide a method for forming a carbon doped silicon containing dielectric layer within a microelectronic fabrication.
A second object of the present invention is to provide a method in accord with the first object of the present invention, wherein the carbon doped silicon containing dielectric layer is formed with a comparatively low dielectric constant while simultaneously having enhanced adhesion with respect to an additional microelectronic layer formed thereupon.
A third object of the present invention is to provide a method in accord with the first object of the present invention and the second object of the present invention, wherein the method is readily commercially implemented.
In accord with the objects of the present invention, there is provided by the present invention a method for forming a microelectronic dielectric layer within a microelectronic fabrication. To practice the method of the present invention, there is first provided a substrate. There is then formed over the substrate a carbon doped silicon containing dielectric layer. There is then treated the carbon doped silicon containing dielectric layer with an oxidizing plasma to form from the carbon doped silicon containing dielectric layer an oxidizing plasma treated carbon doped silicon containing dielectric layer.
Within the present invention, by treating the carbon doped silicon containing dielectric layer with the oxidizing plasma to form therefrom the oxidizing plasma treated carbon doped silicon containing dielectric layer adhesion of an additional microelectronic layer formed upon the oxidizing plasma treated carbon doped silicon containing dielectric layer is enhanced in comparison with adhesion of the additional microelectronic layer in an alternative formed upon the carbon doped silicon containing dielectric layer.
The present invention further provides that the oxidizing plasma which is employed for forming from the carbon doped silicon containing dielectric layer the oxidizing plasma treated carbon doped silicon containing dielectric layer employs at least one of: (1) a substrate temperature of no greater than about 100 degrees centigrade; and (2) an oxidant source gas concentration of no greater than about 20 volume percent.
Under such conditions for the oxidizing plasma, the adhesion of the additional microelectronic layer formed upon the oxidizing plasma treated carbon doped silicon containing dielectric layer is enhanced without compromising a dielectric constant of a carbon doped silicon containing dielectric material from which is formed the carbon doped silicon containing dielectric layer in comparison with a dielectric constant of an oxidizing plasma treated carbon doped silicon containing dielectric material from which is formed the oxidizing plasma treated carbon doped silicon containing dielectric layer.
The present invention provides a method for forming a carbon doped silicon containing dielectric layer within a microelectronic fabrication, wherein the carbon doped silicon containing dielectric layer is formed with a comparatively low dielectric constant, while simultaneously having an enhanced adhesion of an additional microelectronic layer formed thereupon.
The present invention realizes the foregoing object by treating a carbon doped silicon containing dielectric layer, which may comprise a carbon doped silicon oxide dielectric layer, with an oxidizing plasma which employs at least one of: (1) a substrate temperature of no greater than about 100 degrees centigrade; and (2) an oxidant source gas concentration of no greater than about 20 volume percent.
The method of the present invention is readily commercially implemented. The present invention employs methods and materials as are otherwise generally known in the art of microelectronic fabrication, but employed within the context of specific series of process limitations to provide the present invention. Since it is thus a specific series of process limitations which provides at least in part the present invention, rather than the existence of methods and materials which provides the present invention, the method of the present invention is readily commercially implemented.